CORE B - Abstract Virtually all existing pregnancy outcome studies for women with psychiatric illness have suffered from one of two critical shortcomings: 1) a reliance on retrospective reports, even when subjects are prospectively identified, to document the exposures and course of illness during gestation, and 2) a myopic focus on the effects of fetal exposure to psychotropic medication with minimal effort to control for the effects of psychiatric illness/stress and vice versa. The principal goal of Core B, the Human Subjects Core, is to overcome these limitations and provide the Center's fetal and infant outcome projects with a cohort of biological mothers and fathers of babies with wellcharacterized pregnancies with respect to stress, psychiatric illness, psychotropic medication, and other concomitant exposures including tobacco, over-the-counter remedies, etc. In summary, the product of Core B will be prospectively collected longitudinal indices of fetal/infant exposure to both maternal psychiatric illness and the treatments for illness that will in turn will serve as the independent, i.e., exposure, variables in the Center's clinical projects. The specific aims of the Human Subjects Core are: 1) to extend our group's extensive experience in prospective documentation of the perinatal course of mood and anxiety disorders by implementing a naturalistic observational study of a large sample of pregnant women with and without a history of depression and/or anxiety disorders;2) to derive an accurate phenotypic characterization of each participant using a battery of diagnosis specific assessment instruments, 3) to facilitate access to biological samples from this cohort that will be analyzed in other Center cores and projects, and 4) to maintain an electronic repository for the demographic, psychometric, and biological data collected in the Core that can be readily exported for statistical analysis in the Center's projects.